Area Forecast Discussion
Issued by NWS Kansas City/Pleasant Hill, MO

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FXUS63 KEAX 210041

741 PM CDT Wed May 20 2015

Issued at 725 PM CDT WED MAY 20 2015

Have updated the forecast this evening to account for continued
drizzle mention over the next few hours, likely coming to an end
just before/by midnight across the forecast area, tapering off
from the NW to the SE. Additionally, will need to keep a close eye
on whether or not there will end up being a low stratus deck or
fog by the early AM hours as surface high pressure moves in from
the NW. The question will be whether or not the current cloud
cover will continue to lift/partially clear, opening the door for
more of a fog threat. If this partial clearing doesn`t occur, then
will remain a low stratus deck across the area. Winds will
continue to slacken as the night progresses and with plentiful
lower-level/ground moisture in place, any partial clearing/lifting
will assist in fog development.


Issued at 331 PM CDT WED MAY 20 2015

Rain has pushed east of the area this afternoon with just some
residual drizzle in its wake. Drizzle may continue into the early
evening hours before high pressure begins to move in tonight and
dries conditions out. Cloud cover will remain over the area through
the overnight hours keeping temperatures from plummeting. Expect
lows in the upper 30s to mid 40s. Clouds are finally expected to
scatter out tomorrow morning and that will lead the way for mostly
sunny skies tomorrow afternoon. However, weak mixing will keep highs
in the mid 60s which is still some 10 degrees below normal. High
pressure will continue to remain in control through Thursday night
and into Friday morning. Also, on Friday morning, an upper level low
will be located across southern California. This upper level low and
associated upper trough will begin to lift into the Great Basin on
Friday. As it does, a weak lead shortwave will move into the central
Plains. Rain will move across Kansas during the day however, as it
approaches the local area, dry air in place should keep conditions
mainly dry although there will be a slight chance for light showers
across the western CWA Friday afternoon and Friday night. Despite
cloud cover, weak upper ridging will allow highs to rise into the
mid 60s to lower 70s.

The extended timeframe looks to produce several rounds of showers
and thunderstorms. Although, severe weather potential looks low
through the period. PWAT values of 1.25"-1.75" through the holiday
weekend and into the beginning of next week are 2 to 3 standard
deviations above normal. This will lead the potential of continued
and exacerbated river flooding as well as the potential for
localized flash flooding in areas where heavier thunderstorms occur.
Models indicate that there could be an additional 2"-4" of QPF
falling over the area Saturday through Wednesday. This heavy and
prolonged rainfall will be the cause of upper level pattern becoming
slow. On Saturday an upper level high will set up over the
southeastern CONUS causing the upper level trough that was moving
through the Great Basin to slow its eastward progress. This pattern
will only become reinforced through the weekend. Meanwhile, Gulf
moisture will be streaming northward on the back side of the sern
ridge and out ahead of the slow moving approaching trough. This
pattern finally begins to breakdown by mid-week next week however,
models are depicting a surface boundary stalling across the area on
Wednesday and becoming the focus for additional precipitation.


.AVIATION...(For the 00Z TAFS through 00Z Thursday Evening)
Issued at 645 PM CDT WED MAY 20 2015

Cloud deck is slowly lifting with some partial clearing across the
area terminals but still rather OVC in the low to mid-levels.
Surface high pressure currently over western NE will continue to
progress south and eastward through the overnight hours, perhaps
allowing for a bit more lifting/partial clearing of the ceilings.
Tough call as the early AM hours approaches for whether or not it
will end up being a low stratus deck that lingers through sunrise
or fog. Have attempted to capture this trend in this TAF issuance
to give a heads up that MVFR to IFR (and potentially LIFR if
conditions drop considerably) conditions can be anticipated from
the pre-dawn hours through just after sunrise. Winds will continue
to slacken, remaining out of the N to NW.




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